I've replaced the battery on mine, and the experience was extremely frustrating.
It requires a specific screwdriver. The disassembly was quite difficult, and the re-assembly even more.
The battery is soldered on a small PCB and my replacement battery came without that PCB. I don't know how they soldered the two together, but it was very difficult to disassemble (and I do SMT).
After re-assembly, I had some parts that weren't as tight as they should, creating vibrations at high volumes. Obviously waterproofing is lost as well.
To add insult to injury, the new battery only lasted a few months.
I am appalled that such a premium and hard-to-repair product would refuse to work when the battery is empty.